The present invention relates to an electrode, a method of manufacturing the same, a ferroelectric memory, and a semiconductor device.
A ferroelectric memory (FeRAM) retains data by spontaneous polarization of a ferroelectric capacitor using a ferroelectric film. In recent years, a semiconductor device using the ferroelectric memory has attracted attention.
An electrode of the ferroelectric memory is required to have excellent crystallinity and have no gaps from the viewpoint of crystal orientation of the ferroelectric film interposed between the electrodes and reducing diffusion of constituent elements of the ferroelectric film.
Conventionally, the electrode is formed by using a sputtering method at a high substrate temperature, for example. The resulting electrode has excellent crystallinity. However, as shown in FIG. 20, an electrode 100 formed over a substrate 10 by using the sputtering method becomes a columnar or granular crystal having a comparatively large number of grain boundaries. As a result, diffusion of the material for the ferroelectric film formed between the electrodes occurs, whereby characteristics of the ferroelectric memory may be adversely affected. Moreover, if the substrate temperature when forming the electrode is high, the resulting electrode has poor surface flatness in the same manner as the electrode 100 shown in FIG. 20.